DualBoot wrote:And what about log ?Check time between CAS server and Zimbra too.

Can you give me a tip?I got Internal Server Error 500.

The log at /opt/zimbra/log/mailbox.log said that:[btpool0-7891://xxxxx/zimbra/public/preauth.jsp?ticket=ST-4-CvihcFcSVjnL9LGP7ZlY-cas] [] CommonUtils - No route to hostjava.net.NoRouteToHostException: No route to host

Thank you very much for your answer!Before I searched and also had some suggestion remind to check the DNS. So I checked and ensured at my side:1. From CAS server, I can ping email server. And the login process from CAS to LDAP is success. 2. From email Server, I also can ping CAS server normally. I have multi-domain on my email Server. At email Server, I have already added CAS Server IP/ Host name to "/etc/hosts".

I think if you have enabled dnscached service on your mailstore, settings IP and host into /etc/hostsmight be useless. Does you store resolve on the mailstore hostname or the virtualHostname from inside you store ?And does your store or virtual hostname reachable from you store where the error appeared ?